<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <header>header</header>
    <main>
      <div class="center">
        centerwidth=device-width, initial-scale=1.0width=device-width,
        initial-scale=1.0width=device-width,
        initial-scale=1.0width=device-width,
        initial-scale=1.0width=device-width, initial-scale=1.0
      </div>
      <div class="left">left</div>
      <div class="right">right</div>
    </main>
    <footer>footer</footer>
  </body>
  <style>
    body {
      /* width: 50%; */
      min-width: 300px;
    }
    header,
    footer {
      background-color: aquamarine;
    }

    main {
      padding: 0 100px;
      background-color: aqua;
      /* width: 60%; */
    }
    div {
      width: 100px;
      height: 100px;
      float: left;
    }
    .center {
      background-color: red;
      width: 100%;
      /* min-width: 80px; */
    }
    .right,
    .left {
      position: relative;
    }
    .right {
      background-color: yellow;
      left: 100px;
      margin-left: -100px;
    }
    .left {
      background-color: green;
      margin-left: -100%;
      left: -100px;
    }
    main::after {
      content: "";
      clear: both;
      display: block;
    }
  </style>
</html>
